A dangerous heat wave is expected to sweep across much of the central and eastern United States beginning Tuesday and lasting through the July 4 weekend, when the country celebrates its 250th birthday and hosts knockout stages of the World Cup.
Temperatures are forecast to soar above 100F (38C), with high humidity pushing heat indexes even higher, the National Weather Service warned Monday.
Overnight cooling will be limited, with many areas seeing lows in the mid- to upper-70s, the agency added.
That combination of prolonged daytime heat and little nighttime relief is expected to increase the risk of heat-related illness, particularly for the most vulnerable.
“Drink water often. Limit time outside in the afternoon. Check on neighbors,” said the public alert system in the nation’s capital Washington.
